The Everglades is the largest remaining sub-tropical wilderness in the continental United States. The poet of the Everglades, Marjorie Stonemann Douglass, coined a new term for the area: "River of Grass". This wetland, gently sloping from 16 feet to sea level over 100 miles, is essentially a 150-mile-wide slowly moving river. It has alligators and crocodiles, rare and indemic birds, plants, insects and fungi, and the endangered manatee and Florida panther.